Seasonal Shift in Storm Surges at Brest Revealed by Extreme Value Analysis

Markus Reinert (1) , Lucia Pineau-Guillou (1) , Nicolas Raillard (2) , Bertrand Chapron (1)

1 LOPS - Laboratoire d'Océanographie Physique et Spatiale
2 IFREMER - Institut Français de Recherche pour l'Exploitation de la Mer

Global warming changes the Earth's climate in different ways, in particular it influences extreme weather events like storms. Strong storms cause large surges and thus have a signature in the sea level record. While previous studies focused on long-term changes of storm surge amplitude or frequency, changes in the timing of extreme surge events have not been investigated so far. We employed the more than 150 yr long tide gauge record of Brest (France) and found a distinct shift of storm surge timing between the years 1950 and 2000. This caused extreme events to happen about three weeks earlier during the year. We developed for this study two different methods based on statistical extreme value analysis; both methods show this shift of the seasons consistently. Furthermore, by analyzing eight additional stations, we found evidence that this timing shift happened similarly over a large part of the European Atlantic coast. Therefore, we speculate that our measured shift is part of a large-scale climate process.

Keywords: Strom surge; extremes; seasonality; sea level; climate variability; statistical analysis

Domains: Sciences of the Universe [physics]

Markus Reinert, Lucia Pineau-Guillou, Nicolas Raillard, Bertrand Chapron. Seasonal Shift in Storm Surges at Brest Revealed by Extreme Value Analysis. Journal of Geophysical Research. Oceans, 2021, 126, ⟨10.1029/2021JC017794⟩. ⟨insu-03683242⟩